LeetCode daily problem P1437: Are all 1s at least k elements apart?

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Timeline

Timeline

2025-11-17

init

Array

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Problem:

P1437 Whether all1are at least separated bykelements

https://leetcode.cn/problems/check-if-all-1s-are-at-least-length-k-places-away/description/?envType=daily-question&envId=2025-11-17

Note that for two elements at positions i and j, the number of elements between them is j-i-1.

#include <vector>
using std::vector;

class Solution {
    public:
	bool kLengthApart(vector<int> &nums, int k)
	{ //It is enough to check whether adjacent ones are at least k elements apart.
		int last = -1, i, n = nums.size();
		// Find the first 1.
		for (i = 0; i < n; i++) {
			if (nums[i] == 1) {
				last = i;
				break;
			}
		}

		if (last == -1) {
			return true;
		}
		for (i = last + 1; i < n; i++) {
			if (nums[i] == 1) {
				if (i - last - 1 < k) {
					return false;
				} else {
					last = i;
				}
			}
		}
		return true;
	}
};